20 years ago, little Marvin stood curiously in front of his father and asked. "Dad, how do earthworms actually reproduce?" Martin Langhoff doesn't hesitate for long and uses the internet to answer the question. Marvin's question is the starting signal for a family business that seems somewhat miraculous to most people: the Langhoff family runs a worm farm called "Superwurm" and is fully dedicated to breeding the giant redworm, which is used by anglers, as food worms for animals, for hunting or as a natural fertilizer producer.

The family relies on automation. Machines designed by Martin Langhoff himself using Igus components now take over work steps that were previously very time-consuming.

The driverless transport system retrieves Euro containers from the warehouse. © WBM

No maintenance or cleaning for ten years
Martin Langhoff came across Igus products when he was looking for components for his first self-built machine. The worms' feeding and watering process was to be partially automated. Therefore, the components had to function reliably and permanently under difficult operating conditions with dirt, soil and moisture, as the machine was designed for 24-hour continuous operation. In addition, they should not require lubrication so that the worms and soil remain undamaged.

The Drylin R quattro slides with all-plastic bearings, which slide on two parallel shafts, and the E4 E chains have now been in continuous use for ten years and the machine runs perfectly - without maintenance or cleaning.

Superwurm's warehouse is stacked full of Euro containers containing soil and worms. Each of these containers has to be watered once a week and feed is spread on the soil. Until now, the containers have been moved from the warehouse to Langhoff's first feeding and watering machine using a pallet truck. The machine picks up two containers at a time with a compressed air gripper and places them in the next station, where they are sprayed with water and feed is sprinkled on top. The Drylin Quattro slides serve as bearing points for the moving gripper elements.

The containers are automatically watered on the conveyor belt and feed is spread on the ground. © WBM

This machine in particular allows soil and moisture to reach the bearing points. As the sliding elements of the linear guides are made of plastic with incorporated solid lubricants and therefore require no additional lubrication, no lubricant gets into the soil or to the worms. Another advantage of the self-lubricating sliding elements is that dirt cannot adhere to grease or oil. drylin can even be used with sand and dust, as foreign bodies are simply removed from the track by the contact surface between the plastic sliding element and the shaft, similar to a snow shovel.

The harsh operating conditions are no problem for Igus e-chains either. Despite dirt, moisture and constant stress, they guide the cables reliably and particularly quietly. Unsupported lengths are no obstacle.

Robots and AGVs for feeding and watering
Langhoff has developed completely new machines to fully automate the feeding and watering process. These include two robots, a conveyor belt and an automated guided vehicle (AGV). The monotonous work steps involved in feeding and watering no longer have to be carried out by one person full-time, allowing them to concentrate on more demanding tasks. "With the new system, feeding and watering can be carried out around the clock, even when staff are absent. In addition, errors are reduced to an absolute minimum," explains Martin Langhoff, owner of Superwurm.

An Igus E4 energy chain guides and protects the cables on the self-constructed robot arm when the gripper moves up and down. © Igus

The AGV picks up the stacks of Euro containers filled with soil and worms from the warehouse to the new feeding and irrigation system. For this purpose, two parallel synchronously driven Drylin ZLW toothed belt axles (size 1040) including portal center drive are installed in the AGV, which pull the stacks of containers on a trolley into the transport vehicle. This required toothed belt axes with stepper motors (size NEMA23), which can pull containers weighing 120 kilograms.

This complete system is lightweight, requires only low power for operation and is shock and dirt resistant. It is therefore ideal for use in Langhoff's AGVs. The cables are guided by an E6 E-chain to move the toothed belt axles. This increases their service life and protects them from external influences such as crushing. Once the containers have been fully retracted into the AGV, an Igus stepper motor (size NEMA23) closes a barrier to provide additional safety during transportation. This is the only way to obtain CE marking and approval for use in operation.

Once it arrives at the new feeding and watering system, the AGV moves the containers to the first robot, which places them one after the other from the trolley stack onto a conveyor belt. It works with an intelligent gripper that recognizes and corrects the position of the containers and only lifts them when a secure grip is guaranteed. "We needed cost-effective, compact and lightweight components for this," explains Langhoff.

Martin Langhoff shows how the worms are prepared for shipment. © WBM

Shafts are therefore mounted in Igubal ESTM pillow block bearings for opening and closing the gripper. Thanks to special tribopolymers, they can withstand high radial loads, are self-lubricating and therefore maintenance-free. Their vibration-damping material and, of course, their low weight are also conducive to the movement of the robot. An E4 series energy chain is used to guide the cables safely during the fast movements of the robot and to ensure long-lasting cables. In addition, Igus stepper motors (size NEMA23) with gears are used so that the gripper can move the containers onto the conveyor belt.

The containers are then automatically watered on the conveyor belt and feed is scattered on the ground. At the other end of the conveyor belt, a second robot lifts the watered and fed containers from the conveyor belt back onto a trolley, the AGV picks them up and drives them back to the warehouse. If the AGV battery is empty, the vehicle drives itself to the charging station and is ready for use again after 30 minutes. After the optimization phase, the family business plans to use a second identical AGV to speed up the process even further. as